1. Field of the Invention
The present invention relates to methods for manufacturing semiconductor devices. More particularly, the present invention relates to etching methods for manufacturing a semiconductor device such as a capacitor lower electrode.
2. Description of the Related Art
In fabricating semiconductor devices such as dynamic random access memory (DRAM) devices, a chemical solution such as one containing HF and NH4F (“LAL”) or a buffer oxide etchant (“BOE”) is commonly used to etch dielectric layers during various phases of semiconductor fabrication processes.
Unfortunately, air bubbles of various sizes included in the chemical solution often adhere to the surface of a semiconductor substrate, creating serious problems such as an oxide un-etch or not-open phenomenon. As the design rule decreases, this issue becomes more critical, considerably reducing the yield.
Accordingly, an immediate need exists for a novel etching method that can overcome problems caused by air bubbles contained in the chemical solution.